FIGS. 5 and 6 each illustrate an example of a general arrangement of a high-frequency portion of a circuit block in a wireless communication apparatus. FIG. 5 illustrates an example of a receiver device of a TV (Television), and FIG. 6 illustrates an example of a wireless LAN (Local Area Network) card. Note that, those figures illustrate only the portions relates to the present invention for ease of explanation.
As shown in these figures, in a conventional structure of a wireless communication apparatus, the whole circuit or a portion corresponding to high-frequency circuit is formed on a single substrate, and the input/output terminal of the high-frequency circuit is connected to the antenna via a cable or a transmission line. With this structure, the distance of the cable or the transmission line is longer than the connection distance between the respective blocks in the high-frequency circuit.
As one example, FIG. 5 shows a general TV image receiver in which a Yagi antenna 101 and a tuner RF (Radio Frequency) unit 103 are connected via so-called a feeder line of several meters, which is shown as a cable 102 in the figure. The tuner RF (Radio Frequency) unit 103 includes a band pass filter 105, a low-noise amplifier 107, and a mixer 109, which are connected to one another via a 5 mm micro strip line 104, 106, 108 and 110, respectively.
Further, in the case of a wireless LAN card, as shown in FIG. 6, an antenna 209 is soldered to a wireless LAN card substrate 201 as well as a high-frequency circuit; however, an antenna 209 and a band pass filter 207, which is the closest circuit to the antenna 209, are generally connected to a micro strip line 210 of several centimeters of 50Ω. The RFIC203 connected to a baseband IC 202, a transmission power amplifier 205, a low-noise amplifier 213, a switch 211 and a band pass filter 207 are connected to one another via 5 mm micro strip lines 204, 214, 206, 212 and 208, respectively.
This structure is based on the fact that a high-frequency circuit block may be stored inside a TV image receiver, in a card-slot of a personal computer, or in a housing of the TV set, but the antenna section is preferably used in a free space, i.e., without obstacle objects around, in terms of obtaining good sensitivity, so that the antenna section tends to be away from the circuit part.
Further, even when stored in a housing on the same substrate, the high-frequency circuit block is generally covered with a shield casing so as to prevent unwanted radiation. For this reason, the distance between the antenna and the high-frequency circuit block is normally longer than the connection distance between other blocks.
Referring again to FIGS. 5 and 6, in which FIG. 5 illustrates the case where the antenna is away from the main body, and FIG. 6 illustrates the case where the antenna is disposed on the wireless apparatus substrate.
Here, FIG. 7 shows an alternative in which the antenna and a part of the wireless apparatus are stored in the same housing, which is separated from the main body of the wireless apparatus. This structure is used for a satellite broadcast receiver device, and deals with ultra high frequency band of 12 GHz, thus requiring temporary conversion of 12 GHz wireless frequency into 1 GHz intermediate frequency band. For this function, this structure has an individual down converter section, which is provided as a circuit block.
Further, because of the characteristic of satellite broadcast receiving, a parabola antenna 303, which is a kind of open antenna, is used instead of a linear antenna, and therefore, the structure requires a certain volume of a down converter feed bone 304 which is supported by a feed bone supporter 307. In this structure, a down converter feed bone 304 may also be used as a housing of the down converter.
For these reasons, it is a general way that the substrate where the down converter is formed is unified to the down converter feed bone 304, and is placed in the parabola antenna 303 in the vicinity of a focal point of a reflection mirror 306 supported by a parabola antenna brace 305. then, the down converter (not shown) of the down converter feed bone 304 converts a signal of 12 GHz (wireless frequency) into a signal of 1 GHz (intermediate frequency) causing less transmission loss. The converted signal is then inputted to an indoor satellite broadcast receiver tuner 301 by a coaxial cable 302 of several meters.
In the down converter feed bone 304 uses wiring formed in a receiver circuit structure for dealing with ultra high frequency. Therefore, there are some difficulties for regulating the connection distance between the respective circuit blocks.
Note that, prior art to be referred for the present invention may be, for example, Japanese Laid-Open Patent Application Tokukaihei 07-288488/1995 (published on Oct. 31, 1995), Tokukai 2001-274723/2001 (published on Oct. 5, 2001), Tokukaihei 05-160635/1993 (published on Jun. 25, 1993), Tokukaihei 07-193423/1995 (published on Jul. 28, 1995), Tokukaihei 08-316870/1995 (published on Nov. 29, 1996), Tokukaihei 03-102922/1991 (published on Apr. 30, 1991), and a magazine called “hardware for brand-new wireless LAN system (transistor technology July issue, 2001)”.
Incidentally, with recent development of silicon (Si) integrated circuit which becomes now compatible with high frequency wave, a silicon RFIC (Radio Frequency Integrated Circuit), which had dealt with only intermediate frequency band, has become compatible with wireless frequency.
Accordingly, in many of wireless systems of several GHz or lower GHz, a down converter or an up converter is no longer included as an individual block.
Further, in prior art, the performance of the apparatus has been increased by improving performance of a power amplifier handling wireless frequency, or a low-noise amplifier, which are the closest active circuit to the antenna, and by improving performance of the respective circuit blocks, for example, by way of reducing transmission loss of wireless frequency band filter.
However, in a conventional layout of a wireless communication apparatus, such improvements of the power amplifier and the low-noise amplifier have not been fully reflected in the apparatus.